American Airlines Boeing 767 doing a high power engine run had a #1 engine
HPT (High Pressure Turbine) failure.
HPT let go and punctured left wing, #2 engine, peppered fuselage and set
fire to the aircraft.

The turbine disk exited the engine and sliced through the aircraft belly and
lodged in the
outboard side of the #2 engine.

While perhaps indicative of a faulty turbine, remember folks - this test should be considered successful because it weeded out the faulty piece through testing that simultates conditions considerably more severe than what the engine would normally undergo with passengers aboard. While the images are extreme, they show that airlines and airplane manufacturers are doing the right things to keep the flying public safe.